The present invention relates generally to the field of thin film cells that transduce electromagnetic radiation into electrical energy (herein generically called e/m radiation cells), more particularly to thin film solar cells.
Two known types of solar cells are: (i) thin film solar cells; and (ii) crystalline solar cells. Thin film solar cells are segmented into sub-cells in order to optimize cell performance in terms of voltage and current. The segments are reconnected again, preferably in a monolithic way (where the electrical connections are created in situ) without further added interconnection wiring. The segmentation is currently done by: (i) mechanical scribing; or (ii) laser evaporation (also called laser scribing). The conventional process for thin film solar cell segmentation includes the following scribe operations: (i) deposit and scribe into sub-cell formations the conducting back contact layer (also called the “lower conducting layer”); (ii) deposit and scribe into sub-cell formations the absorber (that is, the active layer); (iii) deposit and scribe into sub-cell formations the transparent conducting oxide (also called the “upper conducting layer”); and (iv) edge scribe. They are manufactured by large area deposition of thin films. For practical purposes, the module voltage has to be increased by a series connection of several sub-cells. In order to take advantage of monolithic integration, the scribing processes, mentioned in the previous paragraph, are used to mechanically separate, while maintaining electrical connections between, respective sub-cell areas from each other.